Alberto and others,

   thanks for your message.
Yes, I had read that explanation on the reflector, but I am still puzzled,

as I

live in a small village, and the local Telecom told me that  ADSL will be
available here not sooner than at least 6 months. And when they say 6

months,

they mean not less than 12....
I asked my neighbors, but nobody has an ISDN line here. Just plain old

analog.

But ADSL and ISDN can be found in a nearby town, about 5 km from here.
Given that today all telephone lines are buried, I am a bit skeptical

about the

possibility to receive the 17th harmonic of a signal passing in a buried

line

five kilometers from here. But in my life I have learnt that often reality

defies

intuition and reasoning...

Digital networking has been around for some 20 years, with A/D and D/A
conversion at the exchange.  Interconnections between exchanges and the
"network" are entirely with digital format, with data rates of 2 to 156
Mbit/s.  Subscribers still think they have an analogue connection, but it is
only as far as the exchange.  The likes of ADSL or ISDN bring digital format
into the subcriber loop, but that is additional to what I was mentioning in
my earlier comments.

I suggest you "have a listen" to your phone line, using a suitably rated
audio isolation transformer (as per domestic modems) into your PC sound
card, and see what Argo indicates around 136 kHz, and other multiples of 8
or 64 kbit/s.

73, Bob